Interheater for compound compressed-air engines.



No. 868,560. PATENTED 0GT.15, 1907. C. B. HODGES. INTBRHBATBR FOR GOMPOUND GOMPRESSED AIR ENGINES.

APPLIGATION Hmm 001.10. 1904.

` 2 SHEETS-amm 1.

PATENTED OCT. 15, 1907.

G. B. HODGES. INTERHBATER POB. GOMPOUND COMPRESSED AIB. ENGNES.

APPLICATION FILED 00T. 10| 1904.

2 SHEETS---SIUETv 2.

FIGB

the appropriate shifting of the UNITED STATESUA (,llAR/LES BOWEX HODGES, OFA

PATENT @FFI (1E,

PITISBURG, PENNSYLVA-Nl .\A

To all 'whom it may concern:

Be it known that l, CHARLES BOWEN Honons, residing at Pittsburg. in the county of Allegheny and l State of Pennsylvania, a citizen of the United Sta-tes. have invented or discovered a certain newand useful Improvement in Interheaters for Compound Compressed-Air Engines, of which improvement the fol lowing is a specification.

My invention concerns*inter-heaters for compound compressed-air engines` and the object of my improvements is an interheat er designed and adapted to take heat irom the atmosphere in such quantities as to be cflicicnt in service. l

In the accompanying drawings which form part of this specification, Figure 1 shows diagrammatically and in longitudinal elevation a compound compressedair locomotive engine to which my improvement is applied. In this figure 4the valve-chest and cylinden. at one side of the locomotive and the interheater are shown partly in section. F ig. 2 is a transverse vertical section on the line Il--II, Fig. 1. Fig. 3 is a vertical sectional View showing my interheater in detail, and illustrating a modification of the form shownv in Figs. 1 and 2. Fig. 4 is a view similar to Fig. 3, illustrating a further modification. Parts which are repeated in the several figures hear the same reference numerals in each case. l

In `the drawings, l represents the main storage tank of a compressed-air. locomotive, arranged after the manner of and resembling in shape the boiler of a steam locomotive; 2 is the auxiliary reservoir; 3 is the high- I pressure cylinder; and 4 the low-pressure cylinder; 5 is the interheater. l i

From the auxiliary reservoir, 2, a pipe, 21, leads to r the high-pressure valve-chest, 22, whence it passes on valve, 23, to high-pres sure cylinder, 3, and drives the piston, 32, therein. Upon the appropriate movement of valve 23, the air (ha-ving done its Work in cylinder passes from cylinder`3 through a pipe 3l 'to interheater 5. From interheater 5 the air passes through a pipe, 51,1;0 valvechest, 42, of low-pressure cylinder 4. The appropriate movement of the valve in valve-chest 42 admits the air into the low-pressure cylinder, where it performs its work in driving the piston contained therein, andiwhence it esc nes on the further shifting of the valve and passes into an exhaust pipe, 4l, through which it escapes to the atmosphere. I preferably carry the air through pipe 4l to interheater 5. where it performs the oice which I shall presently describe. i'

The interheater consists in general terms of a receptacle for the compressed air as Vit passes from the highpressure cylinder, and before it enters the low-pressure cylinder, such receptacle having a surface of rela-tively great extent, for the purpose of receiving and imparting to the compressed air contained .within it, the heating Specification of' Letters Patent.

Application tiled October10,190'4. Serial N0. 227,862.

receptacle consists of a fluid-enveloped coil Patented Oct. 15, 190'?. v

effect of the atmosphere. It will be understood that i this receptacle may he of any suitable or desired construction, and so arranged in relation to the engine that a movement of atmospheric air along its surface will he caused by or during the operation of the engine.

, I have found'it preferable to make this receptacle cylindrical in form, and to furnish it with a plurality of longitudinally extending tubes through which atmospheric air is caused to pass. This is illustrated in Figs. l and 2 of the drawings, wherein the receptacle itself is indicated at 53, and the tubular flues for the atmos pheric air are indicated` at 52. This receptacle heing soy disposed and arranged that atmospheric air is caused to flow over the surface, and thus to impart a suhstantial amount of heat to the chilled air contained within` it. various means may be employed for causing this 5 flow of atmospheric air over the surface. The draw* ings show the invention applied to a locomotive engineA and while any desired construction and arrangement of atmospheric heating receptacle may he employed, it is preferred to employ the exhaust from the low-pressure cylinder to produce the draft of air over the heat ing surface oi the receptacle. In Figs. l and 2 I have shown a flared orifice. 54, into which the fines 52 open. Into this I conduct, through pipe 4], the exhaust from the low-pressure cylinder, and hy causing this exhaust.

to be projected into the flared orifice 54, I produce the desired draft of atmospheric air through the tlues 52 and over the heating surfaces oi the receptacle 53.

An alternative Construction is shown in Fig. 3, where, in place of a cylindrical receptacle provided with longitudinal flues, -the receptacle consists of a coil of pipe, 53a, arranged within a casing, 52, andthe draft is caused to flow through this casing. As before, I employ the fiared orifice 54, which in this case forms a continuation of the casing 52H. l

In Fig. 4 a further modification is illustrated; the of pipe, 53h, contained within a casing, 52", and so arranged that a current of atmospheric air may he caused to pass through the casing and over the exterfdetl sur= face of the coil. As in Fig. 3, the casing 52b is continued in a flared orifice, 54, into which the exhaust from the low-pressnre cylinder is directed for the purpose of causing a flow of air. The object ot the iuid envelop is to equalize the heating effected. It Will be understood that, as the engine starts and stops and changes its speed, the amount of c old air flowing from the hghpressure cylinder to bte-regenerated in the interheater will vary, and accordingly the amount of neat absorbed in the interheater will vary in quantity. By providing a liquid envelop for the receptacle I am able to store the heat of the atmospherev in this liquid envelop, and hold it that it .may be available Wlien there is an increase in the flow of cold compressed air. Intliis case I .not only take advantage parat-us, 'I have oithe equalizing influence oi the liquid envelop, but at the same time I take advantage of the actual heating power of the liquid itself, and thisis a matter of considerable moment. While the relative volumesot the liquid which i'orms the envelop and o the air which passes within the receptacle are very unequal; the number of heat units in a given volume of liquid is immensely greater than in an equal volume o air. i As a certain volume oi water contains more heat units than an equal volume of air at the same temperature, by increasing the volume oi the liquid envelop, it will not only transmit the heat received from the atmosphere to the compressed air, but will also impart some oi its 'heat to the compressed air, and in this way the heating action oi the air is supplemented. Ii for example the liquid envelop contains 500 lbs. of Water at the beginning of a run and the engine moves up a grade using large volumes oi compressed air, the latter in its'fiow to the low pressure cylinder will not only absorb heat units from the air but also-serve to take heat units from the envelop reducing the temperature oi the envelop. When the engine moves down grade, there will be opportunity ior at least a partial restoration to the envelop'o normal temperature. In other words this envelop which will not have a temperature/'above normal atmospheric ternperature, acts as a i'ly Wheel to maintain approxiinatelyuniiorm conditions. This liquid envelop may be constructed in any desired manner; as it is illustrated inl Fig. 4, it surrounds a coil of pipe in'a familiar orin of water-jacket.

The flared orifice 54 o the interheater isshown in theseveral figures of the drawing as directed is pointed is immaterial tol my invention, although practical conditions will determine the direction in specific cases.

In describing the construction of my improved apmade plain 'its operation. When the air passes from the high-pressure cylinder of a com pound engine, it is greatly reduced in temperature, and since the volume oi a body oi gas and the pressure which it exerts are dependent upon its temperature, this very low temperature which theair flowing `irons the high-pressure 'cylinder possesses, reducesfits expansive power, and makes it accordingly less eicientfovr further work. The interheater serves the purpose oi regenerating this air in this sense, that it restores'heat to it; and, in so doing, increases its expansivepower and makes it more eiiicient for work in the low-pressurecylinder. In my apparatus thecold compressed air asit passes from the high-pressure cylin sev- `eral different directions. The direction in which it l l, l

vand. provided with a the exhaust from vthe inder is, in the interheater, subjected to a heating ini'iuence, which causes a rise in lthe temperature, and increases its efficiency; and, since the source of the increase in temperature is the heat of the atmosphere itself, my device besides being simple is economic, and demands little or no attention.

In thedrawings I have shown my invention applied to a locomotive engine, because that is the application in which I have found practical operation. I do not, however, limit myself thereto; and it will be under-` stood that the invention'iis applicable generally to compound compressed-air engines.

I claim herein as my invention.

1. in a compound compressed-air engine in combination with the high-pressure and low-pressure cylinders and their inlets and exhausts, of a receptacle tor compressed air connected with the exhaust from the high-pressure cyllnder and with theinlet to the low-pressure cylinder,nnd menus for causing' a current of air to ow over the surface of the said receptacle operative on the exhaust of nir from thenlow-pressure cylinder. substantially as described.

2. In a compound compressed-air engine, in combination with the high-pressure and low-pressure cylinders und their inlets and exhausts, of a receptacle for compressed air connected with the exhaust from the high-pressure cylinder and with the inlet to the low-pressure cylinder', and a passage for atmospheric air through said receptacle, the

exhaust from the low-ijn'essureA cylinder being so arranged at the discharge end of said air passage as to draw atmospheric air therethrough, substantially as described.

3. In a compoundcompressed air engine in combination with the high-pressure and low-pressure cylinders and their inlets and exhausts, of a receptacle for compressed air connected with the exhaust from the high-pressure cylinder and with the inlet to the low-pressure cylinder', passages for atmospheric air through said receptacles, the exhaust from said low-pressure cylinder being arranged to cause a iiow ot atmospheric airnt normal temperature through the passages, substantially ns described.

4. In a compound compressed-air engine, the combination with the high-pressure and low-pressure cylinders und their inlets and exhausts, of a casing arranged to permit the passage of a current of atmospheric air therethrough flaring outlet, a receptacle for. conipressed air arranged within said casing and connected with high-pressure cylinder and with the inlet to the low-pressure cylinder, the exhaust from the low-pressure cylinder beingl arranged todischarge into the flaring outlet of said casing, substantially as described.

5. An interheater for a compound compressed-nir engine which consists of n receptacle receiving air from the high-pressure cylinder' and delivering nir to the low-pressure cylinder, 4said receptacle beingl provided with a surrounding' fluid envelop, such fluid-enveloped surface being of relatively great extent and arranged and-adapted tov absorb heat from the atmosphere, substantially as described.

In testimony whereof, i have hereunto s'et my hand.

CHARLES BOWEN HODGES.

Witnesses:

ALICE A. Timm, Bueno H, Cnnrs'ry. 

